It is important in the design of wall structures to provide both lateral strength and lateral rigidity. Lateral strength is required to resist horizontal loads due to, for example, wind and earthquake forces. If the wall structure is properly designed and constructed, components of the wall will transfer these horizontal or shear forces to adjacent elements in the load path such as other wall components, floors or foundations.
Lateral rigidity is required to prevent the floors and roof from excessive side-sway. If the walls are sufficiently rigid, they will prevent floor and roof framing members from moving off their supports. In addition, buildings with sufficient lateral rigidity will suffer less non-structural damage and thereby avoid long-term degradation due to cracking and water infiltration.
It has long been common to brace walls or wall sections in buildings in order to provide some lateral strength and rigidity. Generally, this bracing has been provided through either sheathing secured to the outside of the wall or by straps or braces that extend at a diagonal along the outside of the wall. Such sheathing and diagonal bracing do transfer loads and tend to provide some measure of lateral strength and lateral rigidity in the wall. However, because of the location of the sheathing or the bracing, the loads transferred are transferred eccentrically. This, of course, results in the loads tending to twist the wall structure and its components, and consequently these loads are not directly and concentrically transferred to the foundation or other termination points. In the end, such exterior sheathing and exterior bracing does not efficiently transfer shear loads.
Therefore, there has been and continues to be a need for a wall structure or wall module that is designed to efficiently provide both lateral strength and lateral rigidity through a concentric design.